Experimental Study of Multiple Droplet Evaporative Cooling. Final Report. September 1991-December 1992.
Experimental Study of Multiple Droplet Evaporative
Cooling. Final Report. September 1991-December 1992.
(4815 K)
Dawson, H. F.; diMarzo, M.
NIST GCR 93-624; Report 92-1; 116 p. April 1993.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Available from:
National Technical Information Service
(NTIS), Technology Administration, U.S. Department of
Commerce, Springfield, VA 22161.
Telephone:
1-800-553-6847 or 703-605-6000;
Fax: 703-605-6900.
Website: http://www.ntis.gov
Order number: PB93-198463
Keywords:
cooling; drop sizes; droplets; evaporation; solid
surfaces; water; thermal conductivity
Abstract:
Techniques of infrared thermography were used to conduct
an experimental study of the evaporative cooling of a
hot, low thermal conductivity, non-metallic surface
heated by radiation and subject to a random array of
impinging water droplets. A droplet generating and
distributing apparatus and a data acquisition system
employing digital image analysis devices were also
developed and implemented. Real time infrared images of
the heated surface were recorded and digitized using
computer resident fram grabbing hardware and analyzed on
a pizel bases, giving a high degree of thermal and
spatial resolution. From these analyses, the
instantaneous surface temperature distribution and
transient surface temperature profile were obtained for
a range of initial temperatures and impinging mass
fluxes. The surface temperature was found to decay
exponentially with time to a steady state value for the
fluxes used. Three dimensional plots of the temperature
distribution on the surface also showed the significant
lowering of the average surface temperature, and
provided a qualitative description of the cooling
phenomena at various stages during the transient.
Results obtained will be used in the future validation
of a computer model of the phenomena.
